Biofilms are considered indigenous to industrial water systems and may result in a number of serious problems, including fouling of heat exchangers and cooling tower fill materials, microbially-influenced corrosion; reseeding of the water system with biofilm organisms, plugging of orifices or piping, and final product or process stream complications.
It has been determined that biofilms are not merely comprised of monolayers of bacterial cells embedded in a polysaccharide matrix, but rather are heterogeneous assemblages of cells, extracellular polymeric substances (EPS), and abiotic particles (clay, diatom frustules, corrosion and mineral deposits). See W. G. Characklis, "Microbial Fouling," in W. G. Characklis and K. C. Marshall (eds.), Biofilms (John Wiley & Sons, N.Y., 1990), pp. 523-584; R. M. Donlan, "Correlation Between Sulfate Reducing Bacterial Colonization and Metabolic Activity on Selected Metals in a Recirculating Cooling Water System," National Association of Corrosion Engineers, Technical Paper No. 83, Nashville, Tenn. Further, research has demonstrated that microbially-produced polymers responsible for initial bacterial adherence to surfaces may not be the same as those involved in cell-to-cell interactions within the biofilm (the biofilm matrix polymers). M. Fletcher, et al., "Bacterial Surface Adhesives and Biofilm Matrix Polymers of Marine and Freshwater Bacteria," Biofouling, 4:129-140 (1991). J. S. Gill, et al., "Fouling of Film Forming Cooling Tower Fills--A Mechanistic Approach," CTI Journal, 16, 1:10-19 (1995), demonstrated that the matrix EPS will act as a "glue" or matrix for entrapment of clay particles on high-efficiency PVC fill material in recirculating cooling water systems.